khyber is quite soundless but at high speed like above 100 the engine sound chnges a bit even in 5th gear and above 120 it increases further more..... but it is normal as these are not efi soundless engines.... so chek 1st ur car when it is stationary....if engine sound is greater then normal or if it still comes into cabin then chek belts, tappits, and engine acceleration....... if its ok then at high speed many other sounds also come into play these may be due to road, engine, tyres, wheel barings, or air pressure of the environment......as khyber is not fully paked car so sound from outside usually comes inside too